Make Manage Subscription Form customizeable

First thanks for your work and effort into creating this super simple yet flexible plugin. We like to use it for our customers.

Please make the form “Manage your subscription” page customizeable. Right now we need to do extra styling to this form, as you are using a form renderer class. It would be more simpler and flexible to have a form template file where you modify the form as you need to for customization and unifying site layout and style.

Thanks.